Exhibit 12

Potash Corporation of Saskatchewan Inc.

Ratio of Earnings to Fixed Charges

(in millions of US dollars, except ratio amounts)

(unaudited)



|                                                        |  |                        |       |   |      |   |       |      |  |   |       |   |  |         |       |   |  |   |       |  
|------------------------------------------------------- |  | ---------------------- | ----- | - | ---- | - | ----- | ---- |  | - | ----- | - |  | ------- | ----- | - |  | - | ----- | -
|                                                        |  | Year ended December 31 |      
|                                                        |  | 2013                   |       |   | 2012 |   |       | 2011 |  |   | 2010  |   |  | 2009(1) |      
|Net income                                              |  | $                      | 1,785 |   |      | $ | 2,079 |      |  | $ | 3,081 |   |  | $       | 1,775 |   |  | $ | 981   |  
|Income taxes                                            |  |                        | 687   |   |      |   | 826   |      |  |   | 1,066 |   |  |         | 701   |   |  |   | 79    |  
|Share of earnings of equity investees                   |  |                        | (195  | ) |      |   | (278  | )    |  |   | (261  | ) |  |         | (174  | ) |  |   | (134  | )
|Fixed charges                                           |  |                        | 259   |   |      |   | 272   |      |  |   | 300   |   |  |         | 285   |   |  |   | 256   |  
|Amortization of capitalized interest                    |  |                        | 23    |   |      |   | 18    |      |  |   | 14    |   |  |         | 8     |   |  |   |      |  
|Distributed income of equity investees                  |  |                        | 180   |   |      |   | 211   |      |  |   | 128   |   |  |         | 79    |   |  |   | 131   |  
|Interest capitalized                                    |  |                        | (79   | ) |      |   | (102  | )    |  |   | (84   | ) |  |         | (107  | ) |  |   | (68   | )
|                                                        |  |                        |       |   |      |   |       |      |  |   |       |   |  |         |       |   |  |   |       |  
|Total Earnings Available for Fixed Charges              |  | $                      | 2,660 |   |      | $ | 3,026 |      |  | $ | 4,244 |   |  | $       | 2,567 |   |  | $ | 1,245 |  
|                                                        |  |                        |       |   |      |   |       |      |  |   |       |   |  |         |       |   |  |   |       |  
|                                                        |  |                        |       |   |     
|Fixed Charges                                           |  |                        |       |   |      |   |       |      |  |   |       |   |  |         |       |   |  |   |       |  
|                                                        |  |                        |       |   |     
|Interest expensed and capitalized                       |  | $                      | 231   |   |      | $ | 244   |      |  | $ | 273   |   |  | $       | 259   |   |  | $ | 227   |  
|Amortization of debt issue costs                        |  |                        | 5     |   |      |   | 5     |      |  |   | 5     |   |  |         | 5     |   |  |   | 3     |  
|Estimated portion of rent expense representing interest |  |                        | 23    |   |      |   | 23    |      |  |   | 22    |   |  |         | 21    |   |  |   | 26    |  
|                                                        |  |                        |       |   |      |   |       |      |  |   |       |   |  |         |       |   |  |   |       |  
|Total Fixed Charges                                     |  | $                      | 259   |   |      | $ | 272   |      |  | $ | 300   |   |  | $       | 285   |   |  | $ | 256   |  
|                                                        |  |                        |       |   |      |   |       |      |  |   |       |   |  |         |       |   |  |   |       |  
|                                                        |  |                        |       |   |     
|Ratio of Earnings to Fixed Charges                      |  |                        | 10.27 |   |      |   | 11.13 |      |  |   | 14.15 |   |  |         | 9.01  |   |  |   | 4.86  |  
|                                                        |  |                        |       |   |      |   |       |      |  |   |       |   |  |         |       |   |  |   |       |  



|(1) | As the company adopted IFRS with effect from January 1, 2010, our 2009 information is presented on a previous Canadian GAAP basis. Accordingly, our information for 2009 may
not be comparable to the periods 2010 to 2013.
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